Int. J. Speleol. 7 (1975) pp. 339-356. Three New Troglobitic Asellids from Western North America (Crustacea: Isopoda: Asellidael by Thomas E. BOWMAN* Troglobitic isopods of the family Asellidae, comprising about 42 species (Fleming, 1973), are widespread in the eastern United States, mostly in non-glaciated areas, but extending into some glaciated parts of Illinois and Indiana. To the west, tro- globitic asellids range to central Kansas, Oklahoma and Texas. West of this area, if we exclude the 4 Mexican species of Mexistenasellus (Cole and Minckley, 1972; Magniez, 1972; Argano, 1973) which belong to a separate family, Stenasellidae (Henry and Magniez, 1968, 1970), only 2 troglobitic asellids are known from North America: Asellus cali/amicus Miller (1933) from northern California and Canasellus pasquinii Argano (1972) from Veracruz state, Mexico. The 3 new species of- western troglobitic asellids described herein extend the records of blind asellids in North America south to Chiapas state, Mexico, and north to central Alberta, Canada (ca. 53°N), and add a second species from Califor- nia. The new species from Chiapas is very similar to Canasellus pasquinii Argano (1972); the new asellids from Alberta and California show no close affinities with known species. The generic status of North American species of Asellus is still unsettled. Henry and Magniez (1970) divided the species between Canasellus Stammer (1932) and Pseudabaicalasellus Henry and Magniez (1968) except A. tamalensis Harford and A. cali/amicus Miller, which they believed to be closely related to far-eastern forms belonging to Asellus (Asellus) and Nippanasellus Matsumoto (1962). I have indi- cated that this is unlikely for A. tamalensis (see Bowman, 1974); the case of A. cali/amicus will be discussed later in this paper. Fleming (1973) presented arguments in favor of reducing both Pseudabaica- lasellus and Conasellus to synonyms of Asellus. However, the taxonomic characters that Fleming analyzed to support his claim failed to include the basal and labial spurs (Bowman and Holmquist, 1975) and the catch-lobe, characters of the male pleopod 2 of Asellus that clearly separate it from American Asellidae except A. (Asellus) alaskensis Bowman and Holmquist. While I consider Fleming's reduction of Canasellus to a synonym of Asellus unacceptable, I also feel that the assignment by Henry and Magniez of all but a few of the approximately 60 North American species to Canasellus probably over- * Department of Invertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, D.C. 20560, U.S.A. 340 THOMAS E. BOWMAN simplifies the situation. But until enough taxonomic infonnation is accumulated to permit a soundly based generic reassessment, I will follow the French authors. However, in place of Conasellus Stammer (1932) I am using its senior synonym, Caecidotea Packard (1871). For many years American authors assigned their blind species from subterranean waters to Caecidotea and their epigean species to Asellus. Miller (1933) presented' evidence that the species of Caecidotea must have evolved independently a number of times from epigean species, and proposed reducing Caecidotea to a synonym of Asellus, as had been advocated by Forbes (1876) and Chappuis (1927). Mackin and Hubricht (1940) supported the independent status of Caecidotea, and Collinge (1945) went so far as to recognize- separate subfamilies, Asellinae and Caecidotinae, but most specialists have supported Miller's position (Chappuis, 1950, 1953, 1957; Birstein, 1951; Steeves, 1963; Vandel, 1964). I agree with the latter authors, but in accordance with the law of priority use Caecidotea in place of Conasellus. Henry and Magniez (1970) pointed out the seniority of Caeci- dotea, but nevertheless usee Conasellus, saying, "NOllS laissons done aux systema- ticiens du Nouveau.Monde Ie soin de regler ce point de la nomenclature". Caecidotea chiapas, new species (Figures 1 - 39) Material examined. Chiapas Mexico: - Cueva de los Murcielagos, 15 km ESE of San Cristobal de las Casas, collected by J. Cooke, W. Russell, and R. Mitchell, 29 VIII 1972: 6 00 (7.7, 6.6, 6.4, 6.2, 6.2, 5.2 mm), 5 ovigerous 'i''i' (5.5,5.2,5.0,4.7, 4.6 mm), 7 mancas (largest 1.6 mm). - Cueva de los Llanos, 15 km ESE of San Cris- tobal de las Casas, collected by J. Cooke, W. Russell, R. Mitchell, 29 VIII 1972: 200 (7.5,6.0 mm), 3 ovigerous 'i''i' (6.0,5.6,4.6 mm), 2 immature 'i''i' (4.8,4.5 mm). The 7.7-mm 0 from Cueva de los Murcielogos is the holotype, VSNM 152766; the remaining specimens are paratypes. Description. Small, eyeless, unpigmented. Length up to at least 7.7 mm; body slender, linear, about 3.8 times as long as wide; coxae all visible in dorsal view. Margins of head, pereonites, and telson moderately setose. Head twice as wide as long; anterior margin slightly concave, without rostrum; postmandibular lobes broadly rounded. Telson slightly longer than wide; sides subparallel; caudomedial lobe rather low and broad, not sharply delimited. Antenna 1 reaching middle of last segment of antenna 2 peduncle; flagellum of 5 - 7 segments; last 3 segments each bearing esthete.' Antenna 2 reaching pereonite 5; last segment of peduncle about 1.6 times length of preceding segment; flagellum of 25 - 35 segments. Mandibles with 4-cuspate incisors and lacinia mobilis; spine row with 10 spines in left mandible, 12 spines in right mandible. Palp as in fig. 14. Maxilla 1, apex of outer lobe. with 13 robust spines and 1 subtenninal seta; inner lobe with 5 apical plumose setae. Maxilliped with 5 - 6 retinaculae. o pereopod 1 propus about 1.5 times as long as wide; palm defined proximally by 3 robust spines, median process of palm triangular, separated from smaller roun- ded distal process by V-shaped cleft. Dactyl flexor margin with rounded boss proxi- mally and about 4 weak spines distally. 'i' pereopod 1 propus more slender, about NEW TROGLOBITIC ASELLIDS FROM WESTERN N. AMERICA 341 .,,:-. Figs. 1-16. Caecidotea chiapas. 1,0, dorsal; 2, C( head, dorsal; 3-9, lateral parts ofpereonites 1-7, dorsal; 10, telson and uropod, dorsal; 11, 0 left antenna 2, dorsal; 12, left mandible; 13, incisor of right mandible; 14, right mandibular palp; IS, maxilla-I, outer lobe; 16, maxilla 1, inner lobe. 342 THOMAS E. BOWMAN Figs. 17-26. Caecidotea chiapas. 17, <;> maxillipcd; 18, oostegite of <;> maxilliped; 19, c5 pcrcopod 1, lateral; 20, d pereopod 1 propus, medial; 21, d pereopod 1 dactyl, medial; 22, <;> I'crcopod 1, medial; 23, propus and dactyl of <;> pereopod 1, lateral; 24, d pcrcopod 4; 25, ". pereopod 4; 26, d pcrcopod 6. NEW TROGLOBITIC ASELLIDS FROM WESTERN N. AMERICA 343 Figs. 27-38. Caecidotea chiapas. 27,0 pleopod I, anterior; 28, opleopod 2, posterior; 29, opleopod 2 exo- pod, flattened under cover glass; 30, 0 right pleopod 2 endopod tip, posterior; 31, same, ante- rior; 32, <;> pleopod 2, anterior; 33, 0 pleopod 3; 34, 0 pleopod 4, exopod; 35, same, endopod; 36, 0 pleopod 5; 37, 0 uropod, dorsal; 38, <;> uropod, ventral. 344 THOMAS E. BOWMAN 2.5 times as long as wide; palm with 0 - 2 proximal spines, medial and distal pro- cesses absent; dactyl without proximal boss. Pereopod 4 more robust in 0 than in 9; merus and carpus with more spinose flexor margins. ' o pleopod 1 larger thah pleopod 2; protopod about 0.6 length of exopod, with 4 retinaculae. Exopod about 0.6 as wide as long, with plumose setae on distal mar- gin and short naked setules on concave lateral margin. 0 pleopod 2 exopod bent anterolaterally, shape when flattened triangular, with long setae on lateral margin. Endopod slender, curving laterally and tapering distally; tip (cannula) twisted clock- wise, without additional processes. 9 pleopod 2 oval, about 2.4 times as long as wide, with about 10 plumose setae on distal and lateral margins. Pleopod 3 exopod about 1.8 times as long as wide; distal segment about 1.5 times length of proximal segment; marginal setae short, sparse, non-plumose. Pleopods 4'and 5 rather fleshy, without marginal setae; exopod of pleopod 5 with poorly defined transverse suture. Uropods as in figs. 37-38, varying with age and sex; exopod broader in large 00. Etymology. The new species is named for the Mexican state of Chiapas. Relationships. Caecidotea chiapas is closest geographically and apparently also morphologically to the recently described C pasquinii (Argano, 1972) from Vera- cruz state, Mexico, but differs inia number of characters including the following: Left mandible, lacinia 4-cuspaterather than 3-cuspate. Maxilla 1 outer lobe with 13 rather than 11 apical spines. ' 25 20 IS chiapas Fig. 39. Known occurrences of Caeddatea spp. in Mexico. NEW TROGLOBITIC ASELLIDS FROM WESTERN N. AMERICA 345 d pereopod 1, palm of propus with 2 processes rather than 1. Pereopod 4 with grea- ter sexual dimorphism. d pleopod 1 with more concave lateral margin armed with short setae. d pleopod 2-with more curved endoped and long twisted rather than short straight cannula; exopod triangular rather than oval. Uropod with relative- ly shorter proto pod. Distribution of Caeddotea in Mexico. The reported occurrences of Caeddotea in Mexico are shown in fig. 39. C puebla (Cole and Minkley, 1968) the only known epigean species, is considered by Fleming (1973) to be identical with C communis (Say), an inhabitant of the northeastern United States. Disjunct populations of C communis in several Colorado lakes and in Echo Lake, Washington, may have been introduced by man, and its possible artificial introduction into Mexico merits inves- tigation. If Fleming is correct, the occurrence of an isolated Mexican population of C communis is difficult to explain otherwise. The record of Caeddotea in Yucatan is based on Creaser's (1938) report of a single incomplete female from Balam Canche Cave near Chichen Itza.